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摘要
In the present work, nanoscale spherical MnO2 was prepared by hydrothermal method and used as precursor. Then spherical LiMn2O4, LiFe0.06Mn1.94O4 and LiNa0.06Mn1.94Fe0.06O4 were synthesized by 2-step sintering method. Physical chemical characterization and electrochemical performance tests were carried out with various methods such as X-ray diffraction(XRD), scanning electron microscopy(SEM), Electrochemical Impedance Spectroscopy(EIS), Cyclic Voltammetry(CV) and charge-discharge cycling test. The results indicated that LiNa0.06Mn1.94Fe0.06O4 has better rate cycling performance than LiMn2O4. Because it has stable crystal structure and the particles are smaller (about 160 nm). After 100 cycles at 0.5 C rate, the discharge capacity of LiNa0.06Mn1.94Fe0.06O4 was 108.0mAh/g, while that of LiMn2O4 was only 92.2mAh/g. Their retaining capacities were 90.91% and 74.12%, respectively. At 10 C rate, the former has better discharge (34.3mAh/g) than that of the latter. This paper also shows that the composite doping of Na+ and Fe3+ has a positive effect on the Li+ diffusion coefficient and charge transfer resistance.
- 出版日期2018-8
- 单位桂林理工大学
